It is proposed to expand the mass cytological screening of tracheobronchial secretions of patients undergoing general endotracheal anesthesia for the early diagnosis of bronchogenic carcinoma. Special stress will be placed on the group at risk (smoking males, 45 and over). Following our recent discovery of increased percentages of multinucleation of tracheobronchial ciliated cells in patients suffering from extrathoracic malignancies (not affected by sex, age or smoking habit), we will: 1) expand the series to determine if all tumors elicit this phenomenon, 2) conduct an epidemiologic survey to follow up the 16 percent non-cancerous patients with high percentages of multinucleation, 3) study the effects of surgery, chemotherapy and radiotherapy on pre- existent multinucleation, and 4) culture ciliated cells to study the possible causes of multinucleation.